Capital Gains Tax Calculator
Your capital gains tax depends on how long you held the asset and how much other income you have. Long-term gains (held over one year) are taxed at 0%, 15%, or 20% federally; short-term gains are taxed as ordinary income. Investment income above the MAGI floor also gets the 3.8% NIIT.
How to use this calculator
- Enter the trade: Add purchase price, sale price, and holding period in days.
- Enter your tax context: Select filing status, other income, and state of residence.
- Review the tax: See short vs long-term treatment, federal rate applied, NIIT, state tax, and net proceeds.
Assumptions
| Assumption | Value |
|---|
| LTCG breakpoints | Single: $49,450 / $545,050 · MFJ: $98,900 / $613,700 (2026 est.) |
| NIIT floors | $200k single / $250k MFJ MAGI |
| Holding period | >365 days = long-term |
| Basis adjustments | Not modeled (wash sales, ROC, gifts) |
| Loss offsets | Not modeled — single-sale view |
Frequently asked questions
What's the difference between short-term and long-term capital gains?
Assets held one year or less are short-term and taxed at your ordinary income rate. Assets held more than one year are long-term and taxed at the lower federal rates of 0%, 15%, or 20%.
How is my long-term capital gains rate determined?
It stacks on top of your ordinary income. The gain fills the 0% bracket first, then 15%, then 20%, based on 2026 thresholds — roughly $49k / $545k for single, $99k / $614k for MFJ.
What is the Net Investment Income Tax?
NIIT is an extra 3.8% federal tax on investment income (including capital gains) above a MAGI floor of $200,000 single or $250,000 MFJ.
Do states tax capital gains at a lower rate?
Most states tax capital gains at their ordinary rate, with no long-term preference. A handful (like WA, TN, FL, TX) have no state income tax; Washington has a specific 7% long-term capital gains tax above a threshold.
How is the holding period measured?
From the day after you acquired the asset through the day you sold it. If that span is 366 days or more, it's long-term.
Does this include cost basis adjustments?
It uses your entered purchase price as basis. Wash sales, return of capital, and other adjustments are not modeled.
What about qualified dividends?
Qualified dividends use the same 0/15/20 brackets as long-term capital gains but aren't modeled here — this tool is for a single sale event.
Can I offset gains with losses?
Yes — capital losses offset capital gains dollar-for-dollar, then up to $3,000 of ordinary income per year. This tool models a single sale, not a full-year Schedule D.
Is this tax advice?
No. This is an illustrative planning estimate using 2026 brackets and is not tax, legal, or investment advice.
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